src/Pure/Thy/ml_context.ML

added the_context_finished;
eval_wrapper: Output.debug;
simplified antiq signatures;
added basic antiquotations;
tuned;

(*  Title:      Pure/Thy/ml_context.ML
    ID:         $Id$
    Author:     Makarius

ML context and antiquotations.
*)

signature BASIC_ML_CONTEXT =
sig
  val the_context: unit -> theory
  val thm: xstring -> thm
  val thms: xstring -> thm list
end;

signature ML_CONTEXT =
sig
  include BASIC_ML_CONTEXT
  val get_context: unit -> Context.generic option
  val set_context: Context.generic option -> unit
  val setmp: Context.generic option -> ('a -> 'b) -> 'a -> 'b
  val the_generic_context: unit -> Context.generic
  val the_local_context: unit -> Proof.context
  val the_context_finished: unit -> theory
  val pass: Context.generic option -> ('a -> 'b) -> 'a -> 'b * Context.generic option
  val pass_context: Context.generic -> ('a -> 'b) -> 'a -> 'b * Context.generic
  val save: ('a -> 'b) -> 'a -> 'b
  val >> : (theory -> theory) -> unit
  val add_keywords: string list -> unit
  val inline_antiq: string ->
    (Context.generic * Args.T list -> string * (Context.generic * Args.T list)) -> unit
  val value_antiq: string ->
    (Context.generic * Args.T list -> (string * string) * (Context.generic * Args.T list)) -> unit
  val use_mltext: string -> bool -> Context.generic option -> unit
  val use_mltext_update: string -> bool -> Context.generic -> Context.generic
  val use_let: string -> string -> string -> Context.generic -> Context.generic
end;

structure ML_Context: ML_CONTEXT =
struct

(** Implicit ML context **)

local
  val current_context = ref (NONE: Context.generic option);
in
  fun get_context () = ! current_context;
  fun set_context opt_context = current_context := opt_context;
  fun setmp opt_context f x = Library.setmp current_context opt_context f x;
end;

fun the_generic_context () =
  (case get_context () of
    SOME context => context
  | _ => error "Unknown context");

val the_local_context = Context.proof_of o the_generic_context;

val the_context = Context.theory_of o the_generic_context;

fun the_context_finished () =
  let
    val thy = the_context ();
    val _ =
      if Context.is_finished_thy thy then ()
      else warning ("Static reference to unfinished theory:\n" ^
        Pretty.string_of (Context.pretty_abbrev_thy thy));
  in thy end;

fun pass opt_context f x =
  setmp opt_context (fn x => let val y = f x in (y, get_context ()) end) x;

fun pass_context context f x =
  (case pass (SOME context) f x of
    (y, SOME context') => (y, context')
  | (_, NONE) => error "Lost context in ML");

fun save f x = setmp (get_context ()) f x;

fun change_theory f =
  set_context (SOME (Context.map_theory f (the_generic_context ())));


(* fact references *)

fun thm name = ProofContext.get_thm (the_local_context ()) (Name name);
fun thms name = ProofContext.get_thms (the_local_context ()) (Name name);



(** ML antiquotations **)

(* maintain keywords *)

val global_lexicon = ref Scan.empty_lexicon;

fun add_keywords keywords =
  change global_lexicon (Scan.extend_lexicon (map Symbol.explode keywords));


(* maintain commands *)

datatype antiq = Inline of string | Value of string * string;
val global_parsers = ref (Symtab.empty:
  (Context.generic * Args.T list -> antiq * (Context.generic * Args.T list)) Symtab.table);

local

fun add_item kind name scan = change global_parsers (fn tab =>
 (if not (Symtab.defined tab name) then ()
  else warning ("Redefined ML antiquotation: " ^ quote name);
  Symtab.update (name, scan >> kind) tab));

in

val inline_antiq = add_item Inline;
val value_antiq = add_item Value;

end;


(* command syntax *)

fun syntax scan src =
  #1 (Args.context_syntax "ML antiquotation" scan src (the_local_context ()));

fun command src =
  let val ((name, _), pos) = Args.dest_src src in
    (case Symtab.lookup (! global_parsers) name of
      NONE => error ("Unknown ML antiquotation command: " ^ quote name ^ Position.str_of pos)
    | SOME scan => transform_failure (curry Antiquote.ANTIQUOTE_FAIL (name, pos))
        (fn () => syntax scan src) ())
  end;


(* outer syntax *)

structure T = OuterLex;
structure P = OuterParse;

val antiq =
  P.!!! (P.position P.xname -- P.arguments --| Scan.ahead P.eof)
  >> (fn ((x, pos), y) => Args.src ((x, y), pos));


(* input/output wrappers *)

val parens = enclose "(" ")";

local

val isabelle_struct = enclose "structure Isabelle =\nstruct\n" "end;";
val isabelle_struct0 = isabelle_struct "";

fun eval_antiquotes txt =
  let
    val ants = Antiquote.scan_antiquotes (txt, Position.line 1);

    fun expand (Antiquote.Text s) names = (("", Symbol.escape s), names)
      | expand (Antiquote.Antiq x) names =
          (case command (Antiquote.scan_arguments (! global_lexicon) antiq x) of
            Inline s => (("", parens s), names)
          | Value (a, s) =>
              let
                val a' = if ML_Syntax.is_identifier a then a else "val";
                val ([b], names') = Name.variants [a'] names;
              in (("val " ^ b ^ " = " ^ s ^ ";\n", "Isabelle." ^ b), names') end);

    val (decls, body) =
      fold_map expand ants ML_Syntax.reserved
      |> #1 |> split_list |> pairself implode;
  in (isabelle_struct decls, body) end;

fun eval verbose txt =
  Output.ML_errors (use_text Output.ml_output verbose) txt;

in

fun eval_wrapper verbose txt =
  let
    val (txt1, txt2) = eval_antiquotes txt;
    val _ = Output.debug (fn () => cat_lines [txt1, txt2]);
  in eval false txt1; eval verbose txt2; eval false isabelle_struct0 end;

end;


(* ML evaluation *)

fun use_mltext txt verbose opt_context = setmp opt_context (fn () => eval_wrapper verbose txt) ();
fun use_mltext_update txt verbose context = #2 (pass_context context (eval_wrapper verbose) txt);

fun use_context txt = use_mltext_update
  ("ML_Context.set_context (SOME ((" ^ txt ^ ") (ML_Context.the_generic_context ())));") false;

fun use_let bind body txt =
  use_context ("let " ^ bind ^ " = " ^ txt ^ " in\n" ^ body ^ " end");


(* basic antiquotations *)

val _ = inline_antiq "typ" (Args.typ >> ML_Syntax.print_typ);
val _ = inline_antiq "term" (Args.term >> ML_Syntax.print_term);
val _ = inline_antiq "prop" (Args.prop >> ML_Syntax.print_term);

val _ = value_antiq "ctyp" (Args.typ >> (fn T =>
  ("ctyp", "Thm.ctyp_of (ML_Context.the_context ()) " ^ parens (ML_Syntax.print_typ T))));

val _ = value_antiq "cterm" (Args.term >> (fn t =>
  ("cterm", "Thm.cterm_of (ML_Context.the_context ()) " ^ parens (ML_Syntax.print_term t))));

val _ = value_antiq "cprop" (Args.prop >> (fn t =>
  ("cprop", "Thm.cterm_of (ML_Context.the_context ()) " ^ parens (ML_Syntax.print_term t))));

val _ = value_antiq "thm"
  (Scan.lift Args.name >> (fn s => (s, "ML_Context.thm " ^ ML_Syntax.print_string s)));

val _ = value_antiq "thms"
  (Scan.lift Args.name >> (fn s => (s, "ML_Context.thms " ^ ML_Syntax.print_string s)));

val _ = value_antiq "context" (Scan.succeed ("context", "ML_Context.the_local_context ()"));

(*final declarations of this structure!*)
nonfix >>;
fun >> f = change_theory f;

end;

structure Basic_ML_Context: BASIC_ML_CONTEXT = ML_Context;
open Basic_ML_Context;